The Empty Gift

The scam: Like many swindles, this one is fairly easy and effective, Stickley says. The fraudster simply goes to stores that display gift cards on shelves or walls. Using a skimming device, smartphone or even a pen and paper, the thief covertly records the codes for unactivated cards, which he puts back on display. The scammer later calls the 800 number listed on the cards to see if a given card has been activated. If so, he uses the codes to make purchases online. That leaves the card's buyer with a worthless piece of plastic.

The lesson: When buying a gift card, make sure the security code is still concealed -- it's often covered with a gray substance. If it's already scratched off, that's a bad sign.